"Lack of expertise on foreign policy has not been a bar to governors in the past," Sigelman said. "The governor may have established his or her record as a competent manager, as a leader, which is obviously the card that George W. Bush played when he was governor. And it's a card that works for governors."
Lately, it's a card that's enjoyed much success. Four out of the last five presidents were governors first.
So, rather than staring down the competition in the halls of the Capitol, senators with presidential ambitions might want to keep their eyes on Democratic Iowa Gov. Tom Vilsack and Republican former Wisconsin Gov. Tommy Thompson, both declared candidates.
Perhaps they should look out for Republican Massachusetts Gov. Mitt Romney and Democratic New Mexico Gov. Bill Richardson, too.
Halperin suggests that for senators to overcome the curse of the last 47 years, they need to be familiar with their own voting record and ready to explain it. They also need to be willing to venture out of Washington, even if it means missing Senate business -- and ready to leave the Senate-speak behind, lest they alienate voters.
Halperin also warns not to give too much power to the dogma of the "curse."
"It's easy to overstate it," he said. "You've got to look at every four years as a separate narrative, and in this narrative Clinton, Obama, McCain and some of the others are strong candidates and aware of the limitations they've got to overcome as senators."
With 661 days to go until Election Day, senators have a lot of tricky votes left to handle, and a good deal of narrative left to write before any of them will be calling the White House home.